Pushbutton switch assembly with pivotable conductive bridging member and multiple conductive path printed circuit board

ABSTRACT

A plurality of push-button switches mounted in a housing having a printed circuit board with conductive paths thereon as a base. Each push-button switch is mounted within the housing by a spring which biases the switch in an upward direction and includes a spring engaging a contact piece so that depression of the pushbutton switch causes the contact piece to rock on a bearing element in contact with a conductive path of the printed circuit board. A spring mounted between the housing and a portion of the contact bridge biases the contact bridge in a first position where a conductive path is formed by the contact bridge between the conductive bearing element and one contact on the bridge and movement of the contact bridge by depression of the push-button switch causes a new conductive path to be formed between another portion of the contact bridge, the conductive bearing element and another contact on the contact bridge.

United States Patent [191 Holzer PUSHBUTTON SWITCH ASSEMBLY WITHPIVOTABLE CONDUCTIVE BRIDGING MEMBER AND MULTIPLE CONDUCTIVE PATHPRINTED CIRCUIT BOARD [75] Inventor:

many

[73] Assignee: Holzer Patent AG, Zug, Switzerland [22] Filed: June11,1971

[21] Appl. No.: 152,163

[30] Foreign Application Priority Data UNITED STATES PATENTS 3,594,5237/1971 Frenzel ..200/157 Walter K. Holzer, Meersburg, Ger- [111 3,73Ifi3[451 May 1, 1973 3,415,966 12/1968 Matthews ..200/157 X 3,531,603 9/1970Ashman ..200/166 PC UX 3,539,749 1 l/l970 MacPheat ..200/159 R PrimaryExamirter-J. R. Scott Att0rneyl Watson, Cole, Grindle & Watson [5 7]ABSTRACT A plurality of push-button switches mounted in a housing havinga printed circuit board with conductive paths thereon as a base. Eachpush-button switch is mounted within the housing by a spring whichbiases the switch in an upward direction and includes a spring engaginga contact piece so that depression of the push-button switch causes thecontact piece to rock on a bearing element in contact with a conductivepath of the printed circuit board. A spring mounted between the housingand a portion of the contact bridge biases the contact bridge in a firstposition where a conductive path is formed by the contact bridge betweenthe conductive bearing element and one contact on the bridge andmovement of the contact bridge by depression of the push-button switchcauses a new conductive path to be formed between another portion of thecontact bridge, the conductive bearing element and another contact onthe contact bridge.

5 Claims, 3 Drawing Figures 'lllllllla Patented May 1, 1973- 3,731,030

VII

INVENTORI v 'ATfO/YMEY Y PUSHBUTTON SWITCH ASSEMBLY WITH PIVOTABLECONDUCTIVE BRIDGING MEMBER AND MULTIPLE CONDUCTIVE PATH PRINTED CIRCUITBOARD The invention relates to in series attachable push- 5 buttonswitches with power contacts and their use on printed circuit boards.

Push-button switches of the initially mentioned type already have beenknown. In the case of these known switching arrangements, however, everyindividual switch must be completely equipped and assembled by itself.Such switches naturally are very costly and expensive. Both the fixedcontacts and the contact bridges must be separately attached in thehousing or on the push-button slide, prior to the assembly of everyindividual switch.

It is the object of the invention to create a push-button switch of theinitially mentioned type, where the drawbacks of known devices will beavoided and with which it will be possible to assemble anumber ofindividual switches very simply and at favorable cost in a switchingaggregate. It should be possible furthermore to produce the contactbridge and fixed contact pieces if possible in only one work step. Theentire switch is to be structured as fiat as possible. Beyond that, theobject of the invention also is to provide a switch usable for electricdevices where the printed circuit boards are built in; in this case theswitch is to be capable of cooperating with the same printed circuitboard of the electric device, so that additional electric connectionswill become superfluous. Besides, a jamming of the push buttons is to bemade impossible.

The previously mentioned objects are achieved in that a printed circuitboard constitutes the lid of the contact housing and in that parts ofthe conductor paths serve as fixed contact pieces on which a contactbridge, which is underv spring tension, has been mounted and which onits part can be moved into the intended switching positions by operationof the pushbutton slide.

According to one embodiment of the invention a compression spring, fixedin the push-button slide, will move the contact bridge, when thepush-button slide is pushed, into a switching position corresponding tothe depressed switching state.

According to a further development of the invention, a guide piece willcenter the push-button switch.

According to an effective development of the invention, the contactbridge is made of flat metal material.

A further development of the invention provides that the contact bridgebe guided by the push-button slide.

According to a further development of the invention, a rib memberrepresents an additional guidance structure, for the contact bridge.

According to another development of the invention, the parts of theprinted circuit boards serving as fixed contact pieces are reinforced bymeans of rivets.

The invention will be explained on the basis of an embodiment presentedby way of example and with the aid ofa drawing.

In the drawing:

FIG. I shows several push-button switches integrated in a push-buttonaggregate;

FIG. 2 shows a longitudinal section through a push button; and

FIG. 3 shows a cross section through the push button, from which theguidance of the contact bridge by the push-button slide becomes clear.

An individual bush button (FIG. 2) consists essentially of a push-buttonslide bar 5, a push-button head 1, 2 as well as a contact bridge 15.Contact bridge 15 connects various fixed contacts with each other, whichare formed by conductor paths 6. Conductor paths 6 are formed'on aprinted circuit board 7. At its fulcrum, contact bridge 15 is supportedby a fixed contact by means of a bearing element 16 and because of itsrocking operation contact bridge 15 can contact various conductor paths.A compression spring 8, which is supported by housing 4 of the pushbutton, holds contact bridge 15 in the position shown in FIG. 2,whenever the push button is not depressed. In this switching state,push-button slide 5 is held in the position shown with the help of anadditional compression spring 17,

which is supported by guide element 3.

With respect to operation of the push-button switch, pushbutton head 1,2 and thus slide 5 are moved in the direction toward printed circuitboard 7, and resulting in that contact bridge 15 is tipped over, and thecontact which had been closed before is opened and the contact which hadbeen opened before is closed. The operation of contact bridge 15 isaccomplished by the fact that, upon depression .of push-button head 1,2, compression spring 9 is moved with the aid of slide 5 to such a pointin the direction toward printed circuit board 7 that compression spring9 will press against contact bridge 15 and will move the latter. In theposition shown in FIG. 2, compression spring 9 does not yet touchcontact bridge 15, so that it would assure a definite switching positionwhen the push-button switch has not been depressed. When releasingpushbutton head I, 2, the push button again will return to its originalposition because of the power of compression spring 17. v

The fixed contacts are made up by conductor paths 6. These fixedcontacts also can be reinforced additionally by means of rivets.Conductor paths 6 can be integral with a printed circuit, as becomesclear from FIG. 1. Printed circuit board 7 represents the cover of thepush button, with which the latter is closed. At the same time, however,printed circuit board 7 can be'the cover of an additional electricswitching device, for example, of a programmed switching mechanism. Inthat case conductor paths 6 also can constitute fixed contacts of theswitching device, or else additional conductor paths may be attached tothe underside of printed circuit board 7, which then can be connected ina manner known per se with conductor paths 6, which have been shown.

As can be seen further in FIG. 1, several individual push buttons can beattached in series in one push-button aggregate. The individual pushbuttons are attached by means of a projection 13 to printed circuitboard 7 via screws or rivets or proper spring clips.

Push-button heads 1, 2 are guided in guide piece 3 and they may haveeither a rectangular or square shape (push-button head 1) or they may beround (push-button head 2). Guide piece 3 either can be slipped on thehousing 4 or it may be an integrated constituent part of said housing.Contact bridge 15 is guided with the aid of push-button slide 5 (FIG.3). For this purpose pushbutton slide 5 effectively will haveprojections 14. Ribs 18 can be used additionally for this lateralguidance of contact bridge 15. To carry out the guidance of the contactbridge altogether with ribs 18 instead of only with slide 5 also ispossible.

In the rest position of the push button, a shoulder 12 of push-buttonslide 5 abuts against an attachment 11 of housing 4 (FIG. 2). The stoparrangement is not described any further for the purposes of thisinvention as such stop arrangements are well known and in the case ofthe present push-button switch all such known stop arrangements can beused.

In the case of a particularly heavy load on conductor paths 6 at theplaces of contact, it is possible to protect these places of theconductor paths by an additional metal surface, for example, withsilver. But the invention also is advantageous in that the additionalmetal coating at the point of contact with bearing element 16 is notabsolutely necessary, because of the relative motion therebetween andtherefore a harmful oxide layer can hardly develop.

In the assembly of the object of the application, first all necessaryparts are inserted in housing 4. As soon as this has been accomplished,printed circuit board 7 is merely put on top, as a result of which thepush button is locked and mounted and the fixed contacts will beattached at the same time. This results in a particularly inexpensivefabrication since all individual parts merely have to be inserted in asingle operational step. Furthermore, in the case of the object of theapplication vis-a-vis the status of the prior art, it advantageouslywill result in a very flat construction. Beyond that, it will be ofadvantage that printed circuit board 7 can be atthe same time aconstituent part of another electrical device, for example, a programmedswitching device. Jamming of push-button heads 1, 2 or push-button slide5, which occurs in the case of the assembly of otherwise traditionalpush-button switches, is impossible in the case of the object of theapplication because of the use of special guide piece 3.

What is claimed is:

l. Push-button switch apparatus, comprising:

a contact housing;

a printed circuit board having thereon conductive paths and forming thebase of said contact housmg;

at least one contact bridge to remove said one contact from saidconductive path and establish engagement of the other of said spacedcontacts with another of said conductive paths, said means including atleast one push-button slide;

a compression spring mounted between said at least one push-button slideand an associated one of said at least one contact bridge for movingsaid contact bridge upon depression of said push-button slide; and anadditional compression spring mounted between said at least onepush-button slide and said housing for biasing an upper portion of saidpush-button slide above an upper surface of said housing.

2. Push-button switch apparatus as in claim 1 wherein said at least onecontact bridge consists of a flat metal strip and further comprisingmeans mounted within said housing for guiding said push-button slidetherein.

3. Push-button switch apparatus as in claim 2 further comprising meansmounted within said housing for preventing lateral movement of said atleast one contact bridge.

4. Push-button switch apparatus as in claim 2 wherein said at least onepush-button slide includes a bifurcated bottom portion, said flat metalstrip is inserted within the ends of said bifurcated portion and saidcompression spring is mounted within the lower portion of said,push-buttonslide between an internal shoulder thereof and said flatmetal strip.

5. Pushbutton switch apparatus as in claim 1 wherein said contacthousing comprises a number of contact housing elements and a number ofcontact bridges each mounted within a respectivecontact housing element,and each of said contact housing elements including a push-button slide.

1. Push-button switch apparatus, comprising: a contact housing; aprinted circuit board having thereon conductive paths and forming thebase of said contact housing; at least one contact bridge mounted withinsaid housing including a conductive bearing element resting on one ofsaid conductive paths and at least one pair of spaced contacts; meansfor biasing said at least one contact bridge so that one contact of saidat least one pair of spaced contacts engages with another of saidconductive paths; means mounted within said housing for moving said atleast one contact bridge to remove said one contact from said conductivepath and establish engagement of the other of said spaced contacts withanother of said conductive paths, said means including at least onepush-button slide; a compression spring mounted between said at leastone pushbutton slide and an associated one of said at least one contactbridge for moving said contact bridge upon depression of saidpush-button slide; and an additional compression spring mounted betweensaid at least one push-button slide and said housing for biasing anupper portion of said push-button slide above an upper surface of saidhousing.
 2. Push-button switch apparatus as in claim 1 wherein said atleast one contact bridge consists of a flat metal strip and furthercomprising means mounted within said housing for guiding saidpush-button slide therein.
 3. Push-button switch apparatus as in claim 2further comprising means mounted within said housing for preventinglateral movement of said at least one contact bridge.
 4. Push-buttonswitch apparatus as in claim 2 wherein said at least one push-buttonslide includes a bifurcated bottom portion, said flat metal strip isinserted within the ends of said bifurcated portion and said compressionspring is mounted within the lower portion of said push-button slidebetween an internal shoulder thereof and said flat metal strip. 5.Push-button switch apparatus as in claim 1 wherein said contact housingcomprises a number of contact housing elements and a number of contactbridges each mounted within a respective contact housing element, andeach of said contact housing elements including a push-button slide.